Blackout curtains help a lot from my experience. I have a hard time falling asleep and staying asleep to begin with and those make a big difference with or without an offset sleep schedule.

Melatonin can also help with sleep duration/quality but its also easy to become dependent on it to fall asleep so not ideal for long term.

Aliexpress is basically amazon with longer shipping time in my experience. Each seller has their own store rating similar to ebay so as long as you exercise judgement ie. Dont buy from brand new stores with 0 feedback or things that are too good to be true and avoid certain things like batteries and storage media unless you know exactly what you’re buying you should be fine. I’ve bought a lot of stuff from there (mostly electronics) and haven’t had bad experiences